Grextras installation

Hi,
I am using gnuradio 3.6.3. I am trying to install precog. So to do
that i have to install gr-extras. But the git repository for gr-extras
says
sorry and nothing else

How should i install gr-extras now?

Yeah not sure what’s going on there, no explanation nothing, but it’s
git and the internet … history is always there, even if unlinked :

Cheers,

Sylvain